Elevating part of a chair back



FIG. 1 is a perspective view of an elevating part of a chair back showing our new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a left side elevational view thereof;

FIG. 5 is a right side elevational view thereof;

FIG. 6 is a top plan view thereof;

FIG. 7 is a bottom plan view thereof; and,

FIG. 8 is a perspective view of an embodiment of an elevating part of a chair back.

The broken lines shown in the drawing are for illustrative purposes only and form no part of the claimed design. 

CLAIM The ornamental design for an elevating part of a chair back, as shown and described. 